Network World - Venture capital investment has rebounded in recent years to healthy levels and one segment of the technology market that's basking in this is cloud computing.

Investments in cloud computing companies rose from $2.1 billion in 2010 to $4.2 billion in 2012, and according to Dow Jones VentureSource’s numbers from 2013, $3.4 billion more was invested through the first three quarters of the year.

“We’re at the early stages of the impact cloud computing will have on the broader market,” says North Bridge Venture Partners’ Michael Skok, who estimates that the cloud has penetrated less than 10% of the roughly $300 billion software market. “That makes people very bullish.”

Startups are forming up and down the cloud stack, from optimizing infrastructure services to offering development platforms. There are applications served from the cloud and new classes of apps that could not have been made without the cloud. Network World has scanned the universe of cloud computing startups founded within the past few years and built this non-exhaustive list of companies (listed in alphabetical order) that give a glimpse of what’s to come in this fast-growing market. (Watch a slideshow version of this story.)

Company: CloudLockFocus: Provides security on top of Google Apps and Salesforce.com by ensuring that sensitive information is encrypted and being handled correctly.Management: CEO Gil Zimmerman was entrepreneur-in-residence at VC firm Cedar Fund before co-founding CloudLock. Before that, he held positions at Sun and EMC. Co-founder Tsahy Shapsa is formerly of Sun and Network Appliances.Founded: 2007, but rebranded in 2010Based: WalthamFunding: $28.2 millionInvestors: Cedar Fund, Ascent Venture Partners, Bessemer Venture PartnersFun Fact: Co-founders Shapsa and Zimmerman served in the Israeli Defense Forces, and Shapsa served in the Israeli Prime Minister’s office as a security team leader. Now, both executives run networking events in the Boston area for Israeli- startups.

The cloud fundamentally changes the security paradigm: Instead of having potentially sensitive information on your own premises behind a firewall, it is now on your provider’s cloud. The key to being comfortable with that model is knowing that your most sensitive data is protected, and that’s where CloudLock focuses.

The company provides data security, encryption and auditing services for workloads, specifically those in the Salesforce.com and Google clouds.

“It’s all about knowing where the crown jewels are stored,” Shapsa says. Once policies are created to instruct CloudLock about what it is looking for, it can identify that information and let users know whether or not it is encrypted, where it is located and who has access to it.

CloudLock can, for example, scan Google Drive and identify all of the credit card and Social Security numbers stored in the cloud to ensure they are encrypted properly. CloudLock uses APIs from the services it is protecting to provide the services, as well as proprietary, custom-made tools. CloudLock itself is hosted on Amazon Web Services and Google Compute Engine. The company runs all of its computations, scans and analysis through AES 256-bit encryption itself, and CloudLock works without opening or reading or storing the content of any documents or sites to ensure security of its customers.